Internal combustion engine arrangement



w. WEYMANN 3,093,123

June 11, 1963 INTERNAL COMBUSTION ENGINE ARRANGEMENT 2 Sheets-Sheet 1 Filed Sept. 12, 1960 INVENTOR WERNER WEYMANN H BY %a,

ATTORNEYS June 11, 1963 WEYMANN 3,093,123

INTERNAL COMBUSTION ENGINE ARRANGEMENT Filed Sept. 12, 1960 2 Sheets-Sheet 2 a} v a: a m 0 I v I I 1 i g 1 1W1 ca W I} I W WERNER WEYMANN BY g A TTORNE 3 '5 United rates atent 3,693,123 ETERNAL COMBUSTIUN ENGINE ARRANGEMENT Werner Weymann, Esslingen (Necirar), Germany, assignor to Daimler-Benz Aktiengeselischaft, Stuttgart-{Interturkheim, Germany Filed Sept. 12, 1960, Ser. No. 55,305 Claims priority, application Germany Sept. 22, 1959 12 Claims. (Cl. 123119) The present invention relates to a hotsstart auxiliary vent device for mixture-compressing internal combustion engines, i.e. gasoline engines.

During operation of carburetor engines, as well as after stoppage thereof, the fuel may flow in liquid as well as in gaseous condition from the carburetor into the air suction line connected ahead of the carburetor and into the mixture suction line. Additionally, during operation of the engine, gas vibrations or oscillations occur at predetermined rotational speeds within the mixture suction line between the valves and the carburetors which cause fuel particles to be discharged or sprayed from the carburetor in finely divided liquid condition as a fuel mist. If the engine is stopped, then the carburetor body may reach such an elevated temperature that the fuel present within the carburetor begins to boil. The fuel vapor bubbles which form under these circumstances within the flat housing occur below the fuel level and have the tendency to rise whereby they push liquid fuel out of the carburetor channels or drag along liquid fuel. The fuel which thus leaves the carburetor contrary to the normal and intended function thereof may also evaporate partly or completely during the heat-up period. The air suction line or inlet line and the mixture suction line terminating within the cylinder are thereby filled with fuel vapor, and there occurs an accumulation of liquid fuel in the relatively low places thereof.

Whereas the mixture suction line arranged between the carburetor and the valves has normally a relatively small volume which may be sucked empty corresponding rapidly during the hot-start operation, the air suction line or intake manifold disposed ahead of the carburetor or carburetors has usually a relatively large volume which is constituted by the air-filter and the common, relatively large intake pipe or manifold, especially with multi-horizontal carburetor installations provided with air distributor pipes or lines. This relatively large volume, when filled with fuel vapor, may enrich, during the hot-start operation, the fuel-air mixture for relatively long periods of time to such an extent that the ignitability boundaryline of the engine is exceeded and the engine starts only with great difficulty.

There exists in the prior art a number of installations which are intended to prevent the exit or discharge of boiling fuel and fuel vapor from the carburetor into the suction lines. A relatively good, though only partial success is achieved, for example, by shifting the floathousing ventilation of the stopped engine from internal to external ventilation. In that case, the vapors may leave the float-housing into the atmosphere.

The overboiling of the fuel is avoided in another known installation of the prior art by realizing the vapor-bubble discharge through open chambers. With these prior art constructions, the discharge aperture serving for purposes of collecting and discharging the vapor bubbles, opens toward the lower part of the fuel nozzle. However, since the vapor bubbles normally seek to rise upwardly, all vapor bubbles are not collected in the discharge aperture; a part thereof leaves through the nozzle so that the intended manner of operation and performance of the carburetor is not fulfilled with these installations.

Another type of installation is known in the prior art "ice in which the vapor bubbles which may occur are lead off or conducted away through upwardly rising channels into an open chamber without taking along any liquid fuel and thereby preventing the harmful overboiling.

These installations, however, are only suited to lead ofi or conduct away the vapor bubbles that may occur during the heat-up period of the carburetor from a predetermined carburetor space, for example, from the float chamber thereof; however, these prior art constructions cannot avoid that during operation of the engine, as a result of gas vibrations or oscillations, liquid fuel and, during the heating-up period, fuel and fuel vapor, which leave in places of the carburetor that cannot be influenced or controlled by reason of the formation of vapor-bubbles, collect or accumulate in the mixture suction line and in the air intake line.

For purposes of eliminating the accumulation of fuel and fuel vapor, undesired for hot-start operation, within the air suction line and the mixture suction line, a hot start auxiliary system is provided in accordance with the present invention which is adapted to be rendered selectively operative in an automatic manner by the pressure of a fluid pump which is kept approximately constant. In particular, according to the present invention, the suction line in front of the carburetor is provided at the deepest place thereof with a discharge automatically opened by a spring force when the engine stands still so that the liquid fuel and fuel vapor may flow oil through such discharge.

However, such discharge aperture has to be closed always with a running engine in order that no unfiltered air can be sucked in. The present invention proposes for that purpose a hydraulic control system. A particularly appropriate control is achieved in accordance with the present invention by arranging at the lowest place of the suction or intake line an aperture, a valve, or the like, the closure body of which is pushed into the closing position thereof either directly or indirectly by the membrane member of a membrane box operative as control member and acted upon by the approximately constant fuel pressure of a preferably electrically-driven fuel pump. The discharge from the suction or intake line is thereby kept open during standstill of the engine by the spring pressure exerted by a suitable spring force and is closed again only during the starting operation by the fuel pressure. During the starting operation, fuel is therefore taken only out of the carburetor and the fuel-air mixture is sucked into the engine cylinders in the proper proportions thereof. The closing of the discharge aperture thereby takes place by a valve which is controlled by a membrane or diaphragm member and is acted upon by the fuel shortly after turning on the electrical ignition, i.e., as soon as the electric supply pump has refilled the carburetor and fuel lines and the normal fuel pressure has been built up again.

Accordingly, it is an object of the present invention to provide a hot-start auxiliary system which obviates the disadvantages and shortcomings encountered with the prior art systems.

Another object of the present invention resides in the provision of a hot-start auxiliary system which effectively precludes, by simple means, an undue enrichment of the fuel air mixture during starting of the engine.

Still another object of the present invention resides in the provision of an auxiliary system, especially for hotstart operation of a gasoline internal combustion engine which precludes effectively the collection of liquid fuel in the suction lines to thereby assure proper starting of the engine under all operating conditions.

Still another object of the present invention resides in the provision of a discharge arrangement for effectively preventing the formation of fuel vapor bubbles that might force fuel unintentionally out of the carburetor float chamber into the suction line system.

These and other objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, two embodiments in accordance with the present invention and wherein FIGURE 1 is a cross-sectional view through a first embodiment of a suction line arrangement provided with a control installation in accordance with the present invention,

FIGURE 2 is a partial cross-sectional view of a modified embodiment provided with a suspended control installation in accordance with the present invention, and

FIGURE 3 is a somewhat schematic over-all view showing the FIGURE 1 embodiment of the control installation for the suction line in relation to other components of the engine assembly.

Referring now to the drawing wherein like reference numerals are used throughout the views to designate like .parts, and more particularly to FIGURE 1, reference numeral 1 designates therein the air suction line or intake manifold which is secured with flange 2 thereof at a horizontal carburetor 21 as schematically illustrated in FIG- URE 3. Carburetor 21 is connected to an engine 20. The air suction line 1 is provided at the lowest place thereof within the area at the lower wall thereof with a discharge aperture 3. The membrane box generally designated by reference numeral 5 is secured by means of bolt members 6 on the projection 4 disposed opposite the discharge aperture 3. Fuel, prior to or during the starting operation of the engine, is forced through line 7, for example, by an electric fuel supply pump 25 from a sump 26 into the membrane box 5 and thereby acts on the disklike diaphragm member 8 of the hydraulic control means. Fuel supply pump 25 is driven by an electric motor 27. An ignition switch 24 is provided between the distributor 22 of the ignition system and battery 23. Switch 24 is also connected to motor 27. The fuel pressure may be kept constant either by the particular pump construction itself or also by a seperate excess pressure valve such as shown in FIGURE 1 by reference numeral 28. The membrane or diaphragm member 8 is secured on a valve rod 9 which carries thereon the plane valve disk 10.

The stroke adjustment of the closure mechanism may be changed by the threaded sleeve connection generally designated by reference numeral 11. The plane valve disk 10 closes the discharge aperture when the diaphragm member 8 is loaded by the admitted fuel under pressure supplied through line 7. If the engine is stopped, i.e. the ignition is interrupted, the electric fuel pump 25 also no longer operates and the fuel pressure returns more or less rapidly to Zero. The spring 12, as a result thereof, opens the discharge bore or aperture 3 through which the fuel and fuel vapor that has already accumulated within the air suction line and/or that might still flow into the air suction line during the next heating-up operation may be discharged.

In FIGURE 2, the control installation is arranged along the lower circumference of the air suction line or intake manifold 1. The membrane box generally designated again by reference numeral 5 is secured with the threaded part 18 thereof within the sleeve portion 19 which, in turn, is secured on the projection 13 of the air intake manifold 1 by means of screws 12. The connection of the fuel pump (not shown) takes place again through line 7. The relatively short valve rod 14 carries the valve disk 15 which connects the discharge aperture 16 with the air intake line 1 through the valve seat 17. The valve disk 15, in order to be adjustable, may also be provided with a threaded sleeve connection 11 with respect to the valve rod 14, as illustrated in connection with the embodiment of FIGURE 1.

While I have shown and described two embodiments in accordance with the present invention, it is understood that the present invention is not limited thereto but is susceptible of many changes and modifications within the spirit and scope of the present invention, and I, therefore, do not wish to be limited to the details shown and de scribed herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

I claim:

1. A hot-start vent system for mixture-compressing internal combustion engines having intake conduit means leading to carburetor means, fuel pump means connected to said conduit means, and means for automatically controlling the etfectiveness of said hot-start system in dependence on the pressure of said fuel pump means including discharge means for said intake conduit means controlled by said pressure in such a manner as to enable fuel and fuel vapor to be discharged from said intake conduit means upon stoppage of said engine.

2. A hot-start vent system for mixture-compressing internal combustion engines having fuel pump means, carburetor means, suction line means leading to said carburetor means, comprising aperture means for said suction line means for enabling the discharge of fuel vapors and fuel collected therein during stoppage of the engine, spring means normally seeking to open said aperture means, and hydraulic control means operatively connected with said pump means for automatically closing said aperture means upon starting of the engine.

3. A hot-start vent system for mixture-compressing internal combustion engines having fuel pump means, carburetor means, suction line means leading to said carburetor means, comprising aperture means for said suction line means for enabling the discharge of fuel vapors and fuel accumulated in said suction line means during stopping of the engine including selectively operable closure means for effectively closing said aperture means, spring means normally urging said closure means in the direction thereof to open said aperture means, and hydraulic control means operatively connected with said fuel pump means for automatically closing said aperture means upon starting of the engine.

4. A hot-start vent system according to claim 3, wherein said aperture means is formed by a discharge opening located essentially at the lowest place of said suction line means, and wherein said hydraulic control means includes membrane means operatively connected with said closure means, said membrane means being loaded by the fluid supplied by said fuel pump means to urge said closure means into the aperture-closing position thereof.

5. A hot-start vent system according to claim 4, wherein said closure means is adjacent said membrane means.

6. A hot-start vent system according to claim 4, wherein said closure means is spaced essentially the diameter of said suction line means from said membrane means.

7. A hot-start vent system according to claim 4, wherein said fuel pump means supplies fuel to said engine at essentially constant pressure.

8. A hot-start vent system according to claim 7, wherein said fuel pump is an electrically driven pump.

9. A hot-start vent system according to claim 4, wherein said membrane means containing a diaphragm member is placed on top along the circumference of said suction line means, and wherein said aperture means is provided in the wall portion of said suction line means opposite said membrane means, said closure means being a valve disk operatively connected with said diaphragm member by a valve rod extending through said suction line means.

10. A hot-start vent system according to claim 4, wherein said membrane means is suspendingly arranged along the lower circumference of said suction line means,

said discharge aperture means being arranged along the lower circumference of said suction line means, and said closure body means being in the form of a valve disk adapted to selectively open and close said aperture means.

11. A hot-start vent system according to claim 2, wherein said aperture means includes a discharge aperture located Within the area of the lowest place of said suction line means, and a planar valve disk operatively connected With said hydraulic control means for selectively opening and closing said aperture means.

12. A hot-start vent device for internal combustion en- 6 gines according to claim 11, further comprising ignition means, and wherein said means for automatically regulating the efiectiveness of the hot-start device is operative to vent vapors from said manifold when said ignition means is turned off.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A HOT-START VENT SYSTEM FOR MIXTURE-COMPRESSING INTERNAL COMBUSTION ENGINES HAVING INTAKE CONDUIT MEANS LEADING TO CARBURETOR MEANS, FUEL PUMP MEANS CONNECTED TO SAID CONDUIT MEANS, AND MEANS FOR AUTOMATICALLY CONTROLLING THE EFFECTIVENESS OF SAID HOT-START SYSTEM IN DEPENDENCE ON THE PRESSURE OF SAID FUEL PUMP MEANS INCLUD- 